can a voice & fax modem detect DTMF - Electronic Circuits Projects Diagrams Free

mdanh2002 · 30th April 2007, 10:02 AM

With a PC modem (voice/fax) can I write a program that monitors the phone line for incoming calls, answers every calls after, say, 5 rings, and, most importantly, turns my phone line into something like the toll-free 1800-xxxx service? I am expecting it to play a voice message 'Welcome to..... Press 1 to.... Press 2 to....' then respond to each digit pressed by the caller accordingly. I know that this has something to do with detecting the DTMF generated when each digit is pressed. But when looking at the modem manual, especially the ATx instructions, I could not find anything useful...

I found in another forum that it is difficult to detect DTMF using a modem but still wonder if this is possible?

ericgibbs · 30th April 2007, 10:09 AM

hi,
you need something like this.

http://www.boondog.com/tutorials/dtmf/dtmf.htm

**Nigel Goodwin** · 30th April 2007, 10:50 AM

Some modems can do this, and actually come with suitable software as well, but such phone systems generally really piss people off - I know they do me!.

ericgibbs · 30th April 2007, 11:27 AM

nigel,
I subscribe to the p*ss off bit.

When I phone my Doctor for an urgent appointment, I go thru at least 4 levels of options, only to be told at the end, 'the surgery is now closed'

justDIY · 30th April 2007, 12:37 PM

you need something called IVR (interactive voice response) software. a voice modem is required, as it passes along voice channel frequencies over its serial connection, including the dtmf. the modem itself is not used in decoding the dtmf, that is done by the IVR software.

check out asterisk it's a great and powerful PBX package, and includes lots of IVR abilities.

mdanh2002 · 30th April 2007, 01:31 PM

Quote:

Originally Posted by ericgibbs

hi,
you need something like this.

http://www.boondog.com/tutorials/dtmf/dtmf.htm

good link for DTMF decoder circuit.

I am thinking of feeding the telephone line input into this decoder circuit, and feed the output to the PC (via parallel port) then write a software to control the process. However, would there be a problem when the modem and my circuit are sharing the same telephone line as input?

Quote:

Originally Posted by justDIY

you need something called IVR (interactive voice response) software. a voice modem is required, as it passes along voice channel frequencies over its serial connection, including the dtmf. the modem itself is not used in decoding the dtmf, that is done by the IVR software.

check out asterisk it's a great and powerful PBX package, and includes lots of IVR abilities.

great suggestion for a software approach. Especially when it's under GNU. I am still trying it.

dandy · 30th April 2007, 07:11 PM

if u hv a voice modem try and download a software called supervoice...i hd some years back written some routines for a internal modem....also chk out google for sdk

as far as my knowledge goes...u can use any voice capable modem which comes in very cheap these days. All of them can / hv dtmf tone generators built into it. As they modem has a built in dialer.

If u need to go for multiport IVR, then look for products like Dialogic or IBM Wave etc...they are multiport and more expensive.

mdanh2002 · 1st May 2007, 03:13 PM

I'm trying out Asterisk. Wasting a lot of money calling my fix line from my mobile phone to test the software.

@dandy: what do you refer to my multiport IVR?

justDIY · 1st May 2007, 08:57 PM

dialogic et all are commercial substitutions for asterisk.

if you're working on this for fun, there's no point in buying a commercial ivr package. as far as multiport, how many ports do you need?

there used to be a dirt cheap Intel soft-modem that worked as an FXO port for asterisk (connected telephone line to computer). I think it's discontinued, but never hurts to search. it should be mentioned on the various asterisk sites.

mdanh2002 · 2nd May 2007, 01:37 PM

Quote:

Originally Posted by justDIY

dialogic et all are commercial substitutions for asterisk.

if you're working on this for fun, there's no point in buying a commercial ivr package. as far as multiport, how many ports do you need?

sorry I don't get what you meant by multiport IVR. Search google but it doesn't seem to helpful. How does multiport IVR differ from single port?

Tested it on my fixed line today. The software picks up the phone but doesn't seem to respond to the key pressed. Also, can I use an infrared modem (named as 'Standard Modem over IR link' by Windows) simulated by a Nokia 6101 handphone for this purpose?

justDIY · 2nd May 2007, 02:17 PM

multiport, as in, multiple phone lines.

many businesses would use PRI cards to route 24 voice channels (equivalent to phone lines) into the pbx at a time.

smaller businesses can use 4 or 8 port FXO cards to connect standard analog phone lines to a pbx.

if asterisk isn't responding to key presses, most likely your modem cannot function as an FXO card, or it's not setup properly. You'll have to look at your initialization strings to make sure the voice modem features are enabled.

mdanh2002 · 4th May 2007, 12:20 PM

Quote:

Originally Posted by justDIY

multiport, as in, multiple phone lines.

Then I'm pretty sure I don't need multiport; just working on this for fun

. I have gotten it working with my Motoralla v56 modem. There was an option in the modem configuration that interconnects the modem speaker to the sound card and plays the voice through the sound card. I discover that this option somehow distorts the original voice, making asterisk unable to detect the DTMF. Disabling the option makes everything work fine.

Btw, in some toll-free 1800 services, there's an option saying 'Press 0 to speak to our customer service officer'. How do I go about implementing this using asterisk? I want something like 'If you hate this system, press 0 to speak to me directly'

Thanks for the useful suggestions!

justDIY · 4th May 2007, 12:22 PM

look at extensions.conf ... this file is where you put all your 'menus'. there's two options for playing back voice prompt files, one doesn't allow interruption, one does.

xheavenlyx · 12th May 2007, 02:59 PM

Actually I was looking for the exact same thing. I too will research Astrix and let you know soon.

My HP laptop has a BroadCom DATA / FAX 56k modem, but not sure if its the "voice" type. I am kinda confused about that. Can anyone clear that?

The main reason of doing that was to accept calls, have a Voice Interface and then ask the user to enter commands (numbers) to control any external device connected to my PC.

So, right now I'm just on the part of trying to accept the call and answer back.

gramo · 13th May 2007, 12:25 AM

Just on DTMF, I'm about to embark on a project with the MT8888 Integrated DTMF Transceiver IC, $5.50 from www.futurlec.com

Here's an extract from the datasheet;

From there, DTMF detection and production is all controlled digitally. This little chip has plenty of real life applications

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30th April 2007, 10:02 AM	(permalink)
mdanh2002	can a voice & fax modem detect DTMF With a PC modem (voice/fax) can I write a program that monitors the phone line for incoming calls, answers every calls after, say, 5 rings, and, most importantly, turns my phone line into something like the toll-free 1800-xxxx service? I am expecting it to play a voice message 'Welcome to..... Press 1 to.... Press 2 to....' then respond to each digit pressed by the caller accordingly. I know that this has something to do with detecting the DTMF generated when each digit is pressed. But when looking at the modem manual, especially the ATx instructions, I could not find anything useful... I found in another forum that it is difficult to detect DTMF using a modem but still wonder if this is possible?

30th April 2007, 10:09 AM	(permalink)
ericgibbs	hi, you need something like this. http://www.boondog.com/tutorials/dtmf/dtmf.htm __________________ Eric "Good enough is Perfect" PIC tutorials: Gramo's: www.digital-diy.net/ Bill's: www.blueroomelectronics.com/

30th April 2007, 10:50 AM	(permalink)
Nigel Goodwin	Some modems can do this, and actually come with suitable software as well, but such phone systems generally really piss people off - I know they do me!. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

30th April 2007, 11:27 AM	(permalink)
ericgibbs	nigel, I subscribe to the p*ss off bit. When I phone my Doctor for an urgent appointment, I go thru at least 4 levels of options, only to be told at the end, 'the surgery is now closed' __________________ Eric "Good enough is Perfect" PIC tutorials: Gramo's: www.digital-diy.net/ Bill's: www.blueroomelectronics.com/

30th April 2007, 12:37 PM	(permalink)
justDIY	you need something called IVR (interactive voice response) software. a voice modem is required, as it passes along voice channel frequencies over its serial connection, including the dtmf. the modem itself is not used in decoding the dtmf, that is done by the IVR software. check out asterisk it's a great and powerful PBX package, and includes lots of IVR abilities. __________________ If you don't have a planet, what good are gold bars? want to contact me directly? gmail gordonthree check out my project website: http://projects.dimension-x.net Favorite numbers: 09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

30th April 2007, 07:11 PM	(permalink)
dandy	if u hv a voice modem try and download a software called supervoice...i hd some years back written some routines for a internal modem....also chk out google for sdk as far as my knowledge goes...u can use any voice capable modem which comes in very cheap these days. All of them can / hv dtmf tone generators built into it. As they modem has a built in dialer. If u need to go for multiport IVR, then look for products like Dialogic or IBM Wave etc...they are multiport and more expensive.

1st May 2007, 03:13 PM	(permalink)
mdanh2002	I'm trying out Asterisk. Wasting a lot of money calling my fix line from my mobile phone to test the software. @dandy: what do you refer to my multiport IVR?

1st May 2007, 08:57 PM	(permalink)
justDIY	dialogic et all are commercial substitutions for asterisk. if you're working on this for fun, there's no point in buying a commercial ivr package. as far as multiport, how many ports do you need? there used to be a dirt cheap Intel soft-modem that worked as an FXO port for asterisk (connected telephone line to computer). I think it's discontinued, but never hurts to search. it should be mentioned on the various asterisk sites. __________________ If you don't have a planet, what good are gold bars? want to contact me directly? gmail gordonthree check out my project website: http://projects.dimension-x.net Favorite numbers: 09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

2nd May 2007, 02:17 PM	(permalink)
justDIY	multiport, as in, multiple phone lines. many businesses would use PRI cards to route 24 voice channels (equivalent to phone lines) into the pbx at a time. smaller businesses can use 4 or 8 port FXO cards to connect standard analog phone lines to a pbx. if asterisk isn't responding to key presses, most likely your modem cannot function as an FXO card, or it's not setup properly. You'll have to look at your initialization strings to make sure the voice modem features are enabled. __________________ If you don't have a planet, what good are gold bars? want to contact me directly? gmail gordonthree check out my project website: http://projects.dimension-x.net Favorite numbers: 09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

4th May 2007, 12:22 PM	(permalink)
justDIY	look at extensions.conf ... this file is where you put all your 'menus'. there's two options for playing back voice prompt files, one doesn't allow interruption, one does. __________________ If you don't have a planet, what good are gold bars? want to contact me directly? gmail gordonthree check out my project website: http://projects.dimension-x.net Favorite numbers: 09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

12th May 2007, 02:59 PM	(permalink)
xheavenlyx	Me too Actually I was looking for the exact same thing. I too will research Astrix and let you know soon. My HP laptop has a BroadCom DATA / FAX 56k modem, but not sure if its the "voice" type. I am kinda confused about that. Can anyone clear that? The main reason of doing that was to accept calls, have a Voice Interface and then ask the user to enter commands (numbers) to control any external device connected to my PC. So, right now I'm just on the part of trying to accept the call and answer back. __________________ www.crazyengineers.com www.scienceforums.net www.Hackaday.com

13th May 2007, 12:25 AM	(permalink)
gramo	Just on DTMF, I'm about to embark on a project with the MT8888 Integrated DTMF Transceiver IC, $5.50 from www.futurlec.com Here's an extract from the datasheet; From there, DTMF detection and production is all controlled digitally. This little chip has plenty of real life applications __________________ Spency. PIC Micro's - Your mind is the limit PIC's and interfacing with other devices - a PIC Basic Guide @ digital-diy.net